Field of the Invention
The present invention relates to a printer or copier apparatus for the printing of a recording medium with magnetically readable toner or toner which is not readable magnetically, in a single apparatus.
In particular, in the USA, it is standard to print checks or financial documents with magnetically readable toner, so that the documents can be read using the MICR (magnetic ink character recognition) method. Magnetically readable toner, called MICR toner, generally contains ferromagnetic particles (such as soft magnetic particles) with a narrow hysteresis loop made of pure iron or other magnetizable materials such as ferrites, iron oxide or magnetite.
Thus, for a wide variety of applications MICR developer mixtures are used that contain as components e.g. 90-99% iron powder, 2-3.5% resin (styrene/acrylic copolymer resin), 0.7-1.4% polymers (styrene/acrylatic copolymer), and 10-20% iron oxide, or e.g. MICR toner with 30-50% styrene/acrylic copolymer resin, 10-20% styrene/acrylate copolymer, 10-30% iron oxide, 3-7% 1-propene polymer, 3-7% epoxy resin, 1-3% lithium stearate and 0.5-2% tetraalkyl ammonium compound. For the black tinting (carbon black), e.g. 0.1-1% artificial pigments (polyvinylidene fluoride) can be contained.
In the following, the term "magnetic" toner is used for an MICR-capable magnetically readable toner. The term "non-magnetic" toner designates a toner which is not readable magnetically, e.g. a standard toner.
For processing in an electrographic printer, the complex composition of MICR developer mixture or, respectively, toner requires particular adaptation to the aggregates involved in the print process, such as for example the developer station, the transfer printing station, the photoconductor, and the fixing station. Among other things, for this reason it has previously been regarded as necessary to use separate printers for printing with MICR toner. These printers are designed exclusively for the processing of MICR toner, with which a processing of standard toners which are not readable magnetically is not possible. For the handling of mixed jobs, two printers have thus been used, namely an MICR-capable printer and a standard printer, or else an MICR-capable printer was used exclusively for the printing. Both methods are uneconomical and require considerable expense.
It is known from U.S. Pat. No. 4,097,139 to provide a copier apparatus with an exchangeable developer station, in order to enable processing of toner with various colors, but variously colored toners of this sort have a chemical composition that is nearly identical and differ only in the pigment color. No adaptation of the processing method is required for the exchange.